Objective: About 50%–60% of all cancer cases will require radiotherapy during their treatment. Nonetheless, radiotherapy facilities are limited in low- and middle-income countries and despite high cancer burden in these regions of the world, only 5% have access to radiation therapy. This study identified the location of radiotherapy centers, the types of radiotherapy machines available and the personnel available in each radiotherapy center in Nigeria. Methods: A cross-sectional questionnaire-based study conducted across the six geopolitical zones of Nigeria from May 2020 to April 2021. A questionnaire having sections on facility profile, status of facility, and human resources, was used to elucidate information for the study. Descriptive statistics (frequency and proportion) were used to describe facilities’ characteristics, status, and human resources available. Results: Out of nine radiotherapy centers evaluated, the majority 33.3% ( n = 3) were found in the southwest geopolitical zone of Nigeria. Out of 10 equipment and accessories evaluated for availability, Ahmadu Bello University Teaching Hospital and University of Benin Teaching Hospital had the highest number of available equipment and accessories 90% ( n = 9) each respectively. Out of the nine centers evaluated, only four centers had at least one functional equipment. The highest number 64.3% ( n = 9) out of the 14 required number of staff in each center was found at University College Hospital. Out of 31 medical physicists identified, the majority 22.6% ( n = 7) was found at University of Nigeria Teaching Hospital. Conclusion: A high percentage of radiotherapy centers in Nigeria lacks the equipment and manpower to function optimally and is located within the southwest geopolitical zone of Nigeria. Therefore, proper investment in the radiotherapy service through private–public partnership, staff training, and equipment upgrade and maintenance could substantially improve the state of cancer care.